a winter Olympics 5000-meter speed-skating event

Question

In a winter Olympics 5000-meter speed-skating event, Hans Holden scored times of 6.85, 7.04, and 6.92 minutes on his first three trials

a) use an inequality to find the times he can score on his last trial so that his average time is under 7.0 minutes

b) in your own words explain the meaning of your answer in part a

Answer 1

Add all the times + "X" for the last run (the fourth run) and divide by 4, this goes on one side of the equation, and on the other is less than 7 so........

7 < (6.85+7.04+6.92+X)/4 and solve for X

multiply both sides by 4, then subtract the number to solve for X

28 < 20.81 + X

7.19 < X, so Hans has to beat 7.19 to get less than 7 seconds average....